Investigation of long-term river water quality variations using different urbanization indices and assessment of common scientific perspectives of urbanization on water quality

This study investigated the water quality variation spanning 30 years (1986–2017) in 16 catchments of Hong Kong against different urbanization indices, namely, built area fraction; population; and product of population and built area fraction. Pearson correlations of three different periods of time (1988–1990, 1998–2000, and 2015–2017) indicated that water quality trends were dependent on the urbanization index. Total solids, nitrite-nitrogen, total phosphorus, electrical conductivity, dissolved oxygen, and flow rate had significant deteriorative trends (Pearson r > 0.5 and p < 0.05) with population and product of built area and population. Results also interpreted that built area fraction and product of built area and population were the worst and best indices that represented urbanization and/or its impacts, respectively. Mann-Kendall test for the entire 30 year period showed that water quality had improved with time with respect to certain water quality parameters (e.g., dissolved oxygen, ammoniacal nitrogen and total suspended solids). The results portrayed that although the urbanization of catchments had increased with time, the river water quality with respect to many parameters showed signs of improvement and the legislative measures implemented seemed to be effective in controlling pollution.     

旋流气浮除油装置预处理含油污水

在河南油田开展旋流气浮除油装置的现场试验,考察进水流量和曝气量对旋流气浮除油装置除油效果的影响。试验结果表明:在进水流量为1.8 m³/h、曝气量为0.5 L/min时,除油率最高达到96.03%;在不添加任何药剂的条件下,装置处理效果稳定;连续运行6 d内,进水含油量为174.57~1 193.15 mg/L时,出水含油量可以保持在137.38 mg/L以下,除油率为58.58%~94.53%。     

美缝剂TVOC释放量与释放规律的测试与分析

提出了环境舱法测试美缝剂总挥发性有机化合物(TVOC)释放量的方法,对市场常见的美缝剂产品的TVOC进行了测试,并研究了美缝剂的TVOC释放规律和主要污染物.同时对美缝剂的甲醛释放量进行了测试.通过对16种环氧树脂美缝剂产品的数据分析显示,美缝剂产品的甲醛释放量风险较低;75%的产品在第7天的TVOC释放量可达到500μg·m^-3以下.但个别产品在28 d时仍有明显的VOC释放,显示其具有长期缓慢释放的特点.美缝剂释放的主要污染物为苯甲醛与苯甲醇,个别产品检出有甲苯和邻苯二甲酸酯类物质.     

Validation of a booted finite element model of the WIAMan ATD lower limb in component and whole-body vertical loading impacts with an assessment of the boot influence model on response

Objective: A novel anthropomorphic test device (ATD) representative of the 50th percentile male soldier is being developed to predict injuries to a vehicle occupant during an underbody blast (UBB). The main objective of this study was to develop and validate a finite element (FE) model of the ATD lower limb outfitted with a military combat boot and to insert the validated lower limb into a model of the full ATD and simulate vertical loading experiments.

Methods: A Belleville desert combat boot model was assigned contacts and material properties based on previous experiments. The boot model was fit to a previously developed model of the barefoot ATD. Validation was performed through 6 matched pair component tests conducted on the Vertically Accelerated Loads Transfer System (VALTS). The load transfer capabilities of the FE model were assessed along with the force-mitigating properties of the boot. The booted lower limb subassembly was then incorporated into a whole-body model of the ATD. Two whole-body VALTS experiments were simulated to evaluate lower limb performance in the whole body.

Results: The lower limb model accurately predicted axial loads measured at heel, tibia, and knee load cells during matched pair component tests. Forces in booted simulations were compared to unbooted simulations and an amount of mitigation similar to that of experiments was observed. In a whole-body loading environment, the model kinematics match those recorded in experiments. The shape and magnitude of experimental force–time curves were accurately predicted by the model. Correlation between the experiments and simulations was backed up by high objective rating scores for all experiments.

Conclusion: The booted lower limb model is accurate in its ability to articulate and transfer loads similar to the physical dummy in simulated underbody loading experiments. The performance of the model leads to the recommendation to use it appropriately as an alternative to costly ATD experiments.     

飞行员人因可靠性定量预测

为有效预测飞行员的人因可靠性,以保障飞行安全,基于认知可靠性与失误分析法(CREAM)的扩展法,建立飞行员人因可靠性定量预测模型。依据飞行员的任务特点,调整认知行为及认知功能。通过优化共同绩效条件(CPC)因子水平等级,并增加新的因子,改进CPC因子依赖规则,用于修正因子的初始评估结果,解决扩展法未考虑因子间关系的问题,从而完成模型的建立。利用回看分析法验证模型的有效性,采用所建立的模型和扩展法分别对已发生的飞行案例进行预测,并与实际发生结果对比分析。结果表明,与扩展法相比,采用飞行员定量预测模型得到的预测结果与案例发生结果所反映的控制模式更为匹配。     

Laboratory investigation of Waelz slag stabilization

Electric Arc Furnace dusts are considered hazardous waste due to their high heavy metals content (zinc, lead, etc.). The Waelz process is one of the most efficient technologies, in terms of capacity and quality, able to recover nearly the 90% of zinc contained in such EAF dusts. Unfortunately, the resulting slag still has eco-compatibility problems, although its mechanical and chemical properties are suitable for civil engineering applications. Stabilization tests, by quartz addition, were performed on EAF dusts in a laboratory furnace. Temperature, treatment time and cooling rate were varied in order to define the best conditions for regulating the formation of a stable microstructure able to hinder the release of substances. Microstructural characterization was carried-out using SEM and XRD analysis. Leaching tests were performed according to EN 12457-2 standards and water analyses were performed using ICP-OES. The best chemical stability was achieved when dust powders were mixed with 20% of silica and water-cooled.     

硫酸雾测试方法若干问题思考

简述了我国硫酸雾测试方法的发展历史,分析和总结了《固定污染源废气硫酸雾的测定离子色谱法》(HJ 544—2016)存在的一些争议和问题,包括硫酸雾的定义、测试方法的干扰控制等。分析认为,相比《硫酸工业污染物排放标准》(GB 26132—2010),HJ 544—2016对硫酸雾的定义更加合理。实验结果表明:硫酸盐是测试方法条件下的目标物,滤筒可以显著地捕捉硫酸盐。9组样品滤筒中,被测目标物所占比例为7.9%~69.1%;滤筒和前吸收液中,被测目标物所占比例为93.7%~97.8%。HJ 544—2016新增加的两级串联碱液吸收瓶可以较完全地捕集穿透滤筒后的硫酸雾,同时也会捕集SO2。SO2会对硫酸雾测试产生正干扰,约42.9%的SO2在被吸收后转化为硫酸雾。     

长庆油田4731B型非金属集输管道老化特性实验研究

为推广非金属复合管在油田集输油领域的应用，明确其在集输环境中的老化特性是关键问题。基于集输油现场的工程条件，针对长庆油田试用的4731B型钢丝缠绕增强复合管，以采出原油、采出水为实验介质，通过挂片实验、水压爆破实验，借助电镜扫描、拉伸测试对复合管内衬层老化行为、拉伸性能以及复合管极限承压与老化特性进行研究。结果表明:采出原油与采出水均可渗透扩散进入内衬层内部，还会发生局部深入渗透；采出原油、采出水的局部渗透速率分别可达3.4，10.6 mm/a；在某些工况下，内衬层表面产生裂纹；短时间（168 h）内的介质渗透甚至裂纹对其机械性能影响较小，而光氧老化影响显著；现场服役813 d后，复合管极限承压下降2.79%，表明复合管承压性能稳定。     

基于多孔环形喷嘴的可燃爆粉尘分散特征的密度效应研究*

为了研究不同密度的可燃爆粉尘在内置多孔环形喷嘴的20 L爆炸特性测试装置中的分散特征，基于负载粒子流方法、耦合DPM动量平衡方程和时间平均 Navier Stokes控制方程组，实现3种不同密度的煤粉、铝粉和锆粉在20 L爆炸测试装置中粉尘分散全过程的数值模拟。研究结果表明:多孔环形喷嘴的分散较为均匀，但是约束管道末端存在局部粉尘残留区，致使爆炸仓内真实粉尘浓度远低于形式浓度；爆炸仓中心位置的最大湍动能随着粉尘密度的增加而减小，只有显著地变化粉尘密度才能展示区分度较高的浓度峰值和抵达浓度峰值的时间。     

瓦斯抽采PC-CAS基封孔材料优化及其膨胀作用分析*

为了研制以硅酸盐/铝酸盐水泥、生石灰、生石膏为主的PC-CAS基封孔材料，采用正交试验优化材料配比、开展膨胀力研究，并用扫描电镜观测料-煤胶结形貌。研究结果表明:材料的最优配比为A2B2C4，其具备优良的流动性、强度及致密性，造浆量达2 100 mL/kg；PC-CAS基材料具有显著的膨胀性，其膨胀力随时间先增大而后趋于稳定，并且该膨胀力随着径向约束的提高而增大；相比于FP材料，PC-CAS基材料产生的膨胀力能够显著降低材料-煤岩界面的空隙并在一定程度上压密煤体内部的裂隙；该材料产生的膨胀力可压密封孔段围岩、提高封孔质量，并为后期“二次注浆”提供保压条件。工业试验结果表明，采用PC-CAS基材料进行封孔可显著改善抽采效果，将原有平均浓度10.11%提升至20.08%。